Add debug counter for unload_units

changing add_iseq_to_process's debug counter name as well for comparison

debug_counter.h

@@ -311,11 +311,14 @@ RB_DEBUG_COUNTER(theap_evacuate)
 /* mjit_exec() counts */
 RB_DEBUG_COUNTER(mjit_exec)
 RB_DEBUG_COUNTER(mjit_exec_not_added)
-RB_DEBUG_COUNTER(mjit_exec_not_added_add_iseq)
 RB_DEBUG_COUNTER(mjit_exec_not_ready)
 RB_DEBUG_COUNTER(mjit_exec_not_compiled)
 RB_DEBUG_COUNTER(mjit_exec_call_func)
 
+/* MJIT enqueue / unload */
+RB_DEBUG_COUNTER(mjit_add_iseq_to_process)
+RB_DEBUG_COUNTER(mjit_unload_units)
+
 /* MJIT <-> VM frame push counts */
 RB_DEBUG_COUNTER(mjit_frame_VM2VM)
 RB_DEBUG_COUNTER(mjit_frame_VM2JT)

mjit.c

@@ -377,6 +377,7 @@ mjit_add_iseq_to_process(const rb_iseq_t *iseq, const struct rb_mjit_compile_inf
     if (!mjit_enabled || pch_status == PCH_FAILED)
         return;
 
+    RB_DEBUG_COUNTER_INC(mjit_add_iseq_to_process);
     iseq->body->jit_func = (mjit_func_t)NOT_READY_JIT_ISEQ_FUNC;
     create_unit(iseq);
     if (iseq->body->jit_unit == NULL)
@@ -388,6 +389,7 @@ mjit_add_iseq_to_process(const rb_iseq_t *iseq, const struct rb_mjit_compile_inf
     CRITICAL_SECTION_START(3, "in add_iseq_to_process");
     add_to_list(iseq->body->jit_unit, &unit_queue);
     if (active_units.length >= mjit_opts.max_cache_size) {
+        RB_DEBUG_COUNTER_INC(mjit_unload_units);
         unload_units();
     }
     verbose(3, "Sending wakeup signal to workers in mjit_add_iseq_to_process");

mjit.h

@@ -138,7 +138,6 @@ mjit_exec(rb_execution_context_t *ec)
           case NOT_ADDED_JIT_ISEQ_FUNC:
             RB_DEBUG_COUNTER_INC(mjit_exec_not_added);
             if (total_calls == mjit_opts.min_calls && mjit_target_iseq_p(body)) {
-                RB_DEBUG_COUNTER_INC(mjit_exec_not_added_add_iseq);
                 rb_mjit_add_iseq_to_process(iseq);
                 if (UNLIKELY(mjit_opts.wait)) {
                     return rb_mjit_wait_call(ec, body);